1. Field of the Invention
The present invention relates to a method for performing printing on a substrate using a pigment- or dye-containing first colorant and a pearl pigment-containing second colorant.
2. Background Art
Unlike ordinary pigments, pearl pigments are luster of pearls and have been utilized as printing inks, cosmetics, and various coating compositions by virtue of their safety, gloss, and feeling of high grade. Further, unlike aluminum powder having a metallic luster, this ink containing a pearl pigment exhibits a rainbow color with a silky sheen having a feeling of high grade. Therefore, images printed using this ink are said to have a rainbow color and a metallic luster at a certain viewing angle. By virtue of this nature, the pearl pigment has received great attention as a colorant in the printing industry. For example, Japanese Patent Laid-Open No. 85269/1996 describes that the utilization of a thermal transfer sheet having a thermally transferable ink layer containing a specific inorganic pearl pigment provides prints having a highly bright metallic luster.
This publication, however, does not propose any specific method for performing printing on a substrate using a pigment- or dye-containing colorant and a pearl pigment-containing colorant. Further, in this publication, there is no specific disclosure to the effect that an image, which is visually perceivable at one certain viewing angle but visually unperceivable at another certain viewing angle, can be printed on a substrate.